Insulin Resistance Is the Beginning of Disease

© Courtney Hunt, MD, 2026

Modern medicine organizes disease into silos.

Cardiology treats the heart.

Endocrinology treats hormones.

Neurology treats the brain.

Oncology treats cancer.

Reproductive medicine treats fertility.

Biology does not operate in silos.

Across nearly every chronic disease, the same metabolic disturbance appears years before diagnosis.

That disturbance is insulin resistance.

Insulin resistance is not simply a blood sugar problem. It represents a breakdown in cellular energy regulation. When that signal appears, mitochondrial metabolism becomes unstable, inflammation rises, hormones destabilize, and the body begins drifting toward disease.

In most patients this process begins decades before symptoms appear.

What Insulin Actually Signals

Insulin is commonly described as a hormone that lowers blood sugar.

In reality insulin is a metabolic instruction signal.

When insulin rises the body receives three commands:

store fuel

stop burning fat

build tissue

Under normal physiology insulin rises briefly after eating and then falls. When insulin falls, the body switches to fat oxidation and mitochondrial respiration.

Humans evolved to move constantly between these two states:

energy storage → energy burning

This metabolic flexibility is one of the defining characteristics of healthy physiology.

Insulin resistance appears when that flexibility disappears.

Hyperinsulinemia: The Silent Phase

Long before blood glucose rises, insulin rises first.

As cells become less responsive to insulin signaling, the pancreas compensates by producing more insulin. Blood glucose may remain normal for years while insulin quietly increases.

This stage—hyperinsulinemia—often persists for decades.

During this time several metabolic changes begin to appear:

fat oxidation declines

mitochondrial efficiency falls

reactive oxygen species increase

inflammatory signaling rises

Patients are often told they are healthy because glucose levels remain normal.

But metabolically the system has already begun to fail.

Insulin Resistance Is a Mitochondrial Problem

At its core, insulin resistance reflects dysfunction in cellular energy systems.

Mitochondria convert nutrients into ATP through oxidative phosphorylation. When mitochondria lose the ability to efficiently oxidize fuel, partially metabolized substrates accumulate inside the cell.

These molecules interfere with insulin signaling pathways and insulin receptors begin to downregulate.

In other words, insulin resistance develops when the cell can no longer properly process incoming energy.

It is not primarily a sugar problem.

It is an energy processing problem.

Why Inflammation Appears

Inflammation is frequently described as the cause of disease.

In many cases inflammation is actually a downstream signal that metabolism has become unstable.

When mitochondria cannot oxidize nutrients efficiently, lipid intermediates and reactive oxygen species accumulate. These molecules activate inflammatory pathways including NF-κB signaling and the NLRP3 inflammasome.

At the same time, chronically elevated insulin suppresses AMPK activation and autophagy—two processes responsible for cellular repair and metabolic cleanup.

The result is predictable:

damaged mitochondria

impaired cellular repair

chronic inflammatory signaling

Inflammation in this context is not the primary problem.

It is the consequence of energy imbalance.

Which is why the equation remains simple: Energy over inflammation.

The Reproductive System Notices First

The ovary is one of the most energy-sensitive tissues in the body.

Oocytes must accumulate enormous mitochondrial reserves before fertilization. Early embryonic development requires intense mitochondrial respiration.

When insulin resistance disrupts mitochondrial function, the ovary often detects the instability first.

Insulin resistance can disrupt

granulosa cell signaling

follicle maturation

ovarian hormone balance

mitochondrial function in the oocyte

Clinically this appears as conditions such as:

PCOS

infertility

declining egg quality

From a biological perspective this makes sense.

If the organism cannot maintain stable energy production, reproduction becomes biologically unsafe.

The Zygote Begins in a Fat-Burning State

The earliest stage of human life reveals something important about metabolic design.

After fertilization the human zygote begins dividing almost immediately. These early divisions require enormous energy, yet the embryo has no access to dietary glucose. There is no bloodstream, no digestion, and no external nutrient supply.

Instead the zygote relies entirely on energy stored inside the egg.

The oocyte accumulates lipid droplets and hundreds of thousands of mitochondria before ovulation. These mitochondria oxidize fatty acids and pyruvate to generate ATP required for early embryonic development.

In other words, the first cell of human life begins in a metabolic environment that resembles a microscopic ketogenic system.

Fat-derived substrates support mitochondrial respiration that powers:

DNA replication

microtubule assembly

cytoskeletal organization

early embryonic cell division

At the moment of fertilization another critical event occurs.

The egg releases a burst of zinc ions known as the zinc spark. This event reorganizes the cytoskeleton, activates embryonic metabolism, and prevents additional sperm from entering the egg.

The spark marks the beginning of a new biological system with its own metabolic rhythm.

From the very first moment of life, human development depends on mitochondrial energy flow.

Human biology—from the zygote forward—is organized around mitochondrial energy production.

When those energy systems destabilize later in life, disease pathways begin to emerge.

Cancer and the Insulin Signal

Cancer cells are also highly responsive to insulin signaling.

Elevated insulin and insulin-like growth factor activate growth pathways including PI3K-Akt and mTOR signaling. These pathways stimulate cell proliferation and suppress apoptosis.

At the same time mitochondrial dysfunction pushes cellular metabolism toward aerobic glycolysis—commonly known as the Warburg effect.

This metabolic configuration allows cancer cells to grow rapidly while bypassing normal metabolic regulation.

Insulin resistance therefore creates a biochemical environment where cancer metabolism can emerge long before tumors become clinically detectable.

The Brain Is Not Protected

The brain is highly sensitive to metabolic disruption.

Neurons require large amounts of ATP to maintain membrane polarization and synaptic signaling. When insulin resistance disrupts neuronal glucose transport and mitochondrial respiration, cognitive function begins to decline.

Insulin signaling defects are commonly observed in neurodegenerative disease, which has led some researchers to refer to Alzheimer’s disease as type 3 diabetes.

When energy delivery becomes unstable, neural systems deteriorate.

Why It Happens Now

Human physiology evolved in environments defined by movement, sunlight, and intermittent food availability.

Modern environments produce the opposite conditions.

constant caloric intake

refined carbohydrates

artificial light at night

sedentary lifestyles

These factors maintain elevated insulin while weakening mitochondrial metabolism.

Over time the metabolic system drifts toward insulin resistance.

Reversing the Signal

Because insulin resistance is fundamentally metabolic, restoring metabolic flexibility requires restoring metabolic signals.

Lower insulin.

Restore fat oxidation.

Repair mitochondrial function.

The biological signals that accomplish this include:

fasting

movement

reduced carbohydrate intake

circadian alignment with natural light

These signals activate AMPK, stimulate autophagy, and allow damaged mitochondria to be repaired.

As insulin levels fall, fat oxidation resumes and cellular energy systems stabilize.

The Earliest Signal of Disease

Long before symptoms appear, insulin resistance begins reshaping metabolism across the body.

It disrupts mitochondrial energy production, alters hormonal signaling, and activates inflammatory pathways across multiple organs.

Medicine treats the downstream diseases in separate silos.

But the biology is unified.

Insulin resistance is often the earliest detectable signal that the body’s energy systems are beginning to fail.

Understanding that signal changes how we think about disease—and how we prevent it.

© Courtney Hunt, MD, 2026

References

Samuel VT, Shulman GI. Mechanisms for insulin resistance. Cell. 2012.

Petersen MC, Shulman GI. Mechanisms of insulin action and insulin resistance. Physiol Rev. 2018.

Youm YH et al. The ketone metabolite β-hydroxybutyrate blocks NLRP3 inflammasome-mediated inflammatory disease. Nat Med. 2015.

Hotamisligil GS. Inflammation and metabolic disorders. Nature. 2006.

Dunning KR et al. Fatty acid metabolism in the oocyte and early embryo. Reproduction. 2014.

Warburg O. On the origin of cancer cells. Science. 1956.

Hunt C. Your Spark Is Light: The Quantum Mechanics of Human Creation. Courtney Hunt Productions.